02 Sensor heater diferances between 4.8/5.3 and 6.0?

It appears that the lower gvw trucks with 4.8/5.3 use the pcm to control the heater for the 02 sensor more actively than the higher gvw 6.0 trucks. I am doing a swap vehicle and put a 6.0 file into the truck. With the headers the 02 sensors take forever to heat up and cycle. I tried a few different files from different models with the same results. When I put a 4.8 file back in the sensors heat up and cycle right away. Wiring from what I can see is identical. Anyone else noticed this? Anyone know where these parameters are located and how I might turn them on in a 6.0 file?

What tuning software are you using? If its tunercat, I was unable to find where you change the O2 sensor timers based on whether or not it is cold or nornal engine temperature. In EFIlive, its under engine calibration>fuel>O2>parameters.

The 02's changed in 03? when going to the newer "LS1B" style '0411' ecm.

No, 2002 was last year of 0411 style PCM(except corvette) which supplied constant voltage to pcm. 2003 is the 1 mb PCM and the ground side of the o2 sensor feeds to the PCM for control. O2 sensors are different.